SOURCE

new Vue({
    el: '#exercise',
    data: {
        value: 'test'
    },
    methods: {
        alertMe: function() {
            alert('alert');
        },
        keydownEvent: function(event) {
            this.value = event.target.value;
        },
        keydownEnter: function(event) {
            this.value = event.target.value;
        }
    }
});

<script src="https://unpkg.com/vue/dist/vue.js"></script>

<div id="exercise">
    <!-- 1) Show an alert when the Button gets clicked -->
    <div>
        <button v-on:click="alertMe">Show Alert</button>
    </div>
    <!-- 2) Listen to the "keydown" event and store the value in a data property (hint: event.target.value gives you the value) -->
    <div>
        <input type="text" v-on:keydown="keydownEvent">
        <p>{{ value }}</p>
    </div>
    <!-- 3) Adjust the example from 2) to only fire if the "key down" is the ENTER key -->
    <div>
        <input type="text" v-on:keydown.enter="keydownEnter">
        <p>{{ value }}</p>
    </div>
</div>